LONGVIEW, Washington (From news reports) -- Eight people are now confirmed to have died following a chemical tank implosion at a paper mill in Washington state on Tuesday, May 26.

The bodies of two people were found earlier this week, before crews recovered the remains of another six victims on Thursday, May 28, Longview fire chief Brad Hannig said in a press conference later that day.

Three more are missing and presumed dead, while a further eight -- including a firefighter -- were injured.

The update comes after a tank containing white liquor, a chemical mixture used to break down wood for making paper, ruptured at the Nippon Dynawave Packaging Co. in Longview on Tuesday morning. Officials estimated that 550,000 to 570,000 gallons of the chemicals remained in the 900,000-gallon tank, according to the outlet.

The incident is one of the deadliest workplace accidents in the U.S. in recent years, and it's thought to be the worst industrial disaster in Washington state's modern history.

The implosion occurred during a shift change, and the six workers whose bodies were found were in an area of the site where workers would go before their shift, Matt Amos, Longview fire battalion chief, said.

Recovery of the bodies has been slow because of the chemicals and other hazards present at the site, Amos explained. Rescue crews have avoided a zone close to the tank due to the risk of it collapsing further, and they've been working with engineers to work out whether some of the damaged buildings near the tank will be safe to enter.

"The priority is ensuring responder safety while treating every victim with the greatest dignity, care, and respect possible," Hannig explained in the press conference. "As individuals are recovered from the site, they undergo decontamination before being transported to the Cowlitz County Coroner's Office for identification and family notification."

Authorities have not released the names of those killed, but some of their loved ones have been confirming names and identities online and setting up fundraisers to support their families.

Gilbert Bernal, a grandfather, was identified as the first victim. "My father was the most selfless man I knew. He worked hard to provide for his family and he loved us so much," said his daughter, Geovana Bernal, in a statement. "He was going to celebrate his 32nd wedding anniversary with mom in just a couple weeks and he loved my son, his first grandson, so much."

The cause of the implosion is still under investigation. The U.S. Chemical Safety and Hazard Investigation Board is investigating the incident, while the Washington State Department of Ecology and the U.S. Environmental Protection Agency (EPA) have been monitoring air and water quality.

Brooks Stanfield, a federal on-scene coordinator with the EPA, said in the press conference that, "not only have we not seen any exceedances of health criteria, we have not actually had a detection of hydrogen sulfide or any of the other air contaminants we might have encountered," describing it as "really good news."